Distribution of extended-spectrum β-lactamase types in a Brazilian tertiary hospital

INTRODUCTION: Epidemiological data on the prevalence of extended-spectrum β-lactamases (ESBLs) are scarce in Brazil despite the fact that these data are essential for empirical treatment and control measures. The objective of this study was to evaluate the prevalence of different ESBLs by type and distribution in a tertiary hospital in southern Brazil. METHODS: We evaluated 1,827 enterobacterial isolates between August 2003 and March 2008 isolated from patients at a tertiary hospital. Samples were identified using a Vitek automated system and were confirmed by biochemical testing. The identified ESBL strains were characterized by phenotypic methods, polymerase chain reaction (PCR), and sequencing. Genetic similarities were evaluated by pulsed-field gel electrophoresis. RESULTS: It was 390 (21.3%) ESBL-producing strains, which expressed the ESBLs CTX-M (292), SHV (84), CTX and SHV (10), TEM (2), and PER (2). CONCLUSIONS: The prevalence of ESBL-expressing strains was high, especially in Klebsiella pneumoniae and Enterobacter spp. CTX-M was the predominant type of ESBL observed, and its genetic variability indicates a polyclonal distribution.

Occurrence and sensitivity profile of extended spectrum beta-lactamase-producing Enterobacteriaceae at a tertiary hospital in Southern Brazil

Abstract: INTRODUCTION: Nosocomial infections are closely associated with antimicrobial drug resistance. One of the most important mechanisms of resistance to β-lactam antibiotics is the production of extended spectrum β-lactamases (ESBLs). The objective of the present study was to evaluate the prevalence and antimicrobial susceptibility profile of ESBL-producing strains and to assess the evolution of antimicrobial drug resistance between 2007 and 2013 at the Hospital São Vicente de Paulo, Passo Fundo, State of Rio Grande do Sul, Brazil. METHODS: We conducted a descriptive, observational, cross-sectional study. Bacterial culture was performed from January to December 2013. The antimicrobial susceptibility profile of these cultures was determined using the disk diffusion method. Phenotypic screening for ESBL production was performed using the disk approximation method. RESULTS : We analyzed a total of 19,112 cultures, 11.5% of which were positive for Enterobacteriaceae. Of these, 30.3% of the isolates were positive for ESBL production, and the most prevalent species was Klebsiella sp. (37.5%). Over 95% of these isolates showed reduced susceptibility to all cephalosporins, aztreonam, and amoxicillin/clavulanic acid. The isolates also showed high sensitivity to the following antimicrobials: amikacin, meropenem, and piperacillin/tazobactam. Overall, the resistance rates among ESBL-producing Enterobacteriaceae decreased from 2007 to 2013. CONCLUSIONS : In our hospital, the increased sensitivity to certain antimicrobial agents seems to be directly related to the implementation of improvements in the methods to prevent and control nosocomial infections in addition to the natural development of other resistance mechanisms.

Arboviral diseases in the Western Brazilian Amazon: a perspective and analysis from a tertiary health & research center in Manaus, State of Amazonas

The Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), located in Manaus, the capital of the State of Amazonas (Western Brazilian Amazon), is a pioneering institution in this region regarding the syndromic surveillance of acute febrile illness, including arboviral infections. Based on the data from patients at the FMT-HVD, we have detected recurrent outbreaks in Manaus by the four dengue serotypes in the past 15 years, with increasing severity of the disease. This endemicity has culminated in the simultaneous circulation of all four serotypes in 2011, the first time this has been reported in Brazil. Between 1996 and 2009, 42 cases of yellow fever (YF) were registered in the State of Amazonas, and 71.4% (30/42) were fatal. Since 2010, no cases have been reported. Because the introduction of the yellow fever virus into a large city such as Manaus, which is widely infested by Aedes mosquitoes, may pose a real risk of a yellow fever outbreak, efforts to maintain an appropriate immunization policy for the populace are critical. Manaus has also suffered silent outbreaks of Mayaro and Oropouche fevers lately, most of which were misdiagnosed as dengue fever. The tropical conditions of the State of Amazonas favor the existence of other arboviruses capable of producing human disease. Under this real threat, represented by at least 4 arboviruses producing human infections in Manaus and in other neighboring countries, it is important to develop an efficient public health surveillance strategy, including laboratories that are able to make proper diagnoses of arboviruses.

Clinical, demographic, and epidemiologic characteristics of hepatitis B virus-infected patients at a tertiary public hospital in Presidente Prudente, State of São Paulo, Brazil

Abstract: INTRODUCTION: Few studies have addressed the primary characteristics of patients infected with hepatitis B virus (HBV) in the general population, especially those living in small- and medium-sized cities in Brazil. We aimed to determine the clinical, demographic, and epidemiologic characteristics of patients diagnosed with HBV who were followed up at an infectious diseases clinic of a public hospital in State of São Paulo, Brazil. METHODS: Medical records of patients aged >18 years and diagnosed with HBV infection between January 2000 and December 2013 were reviewed. RESULTS: Seventy-five patients were enrolled with male-female main infection-associated risk factors; 9 (12%) were co-infected with human immunodeficiency virus (HIV), 5 (6.7%) with hepatitis C virus (HCV), and 3 (4%) were co-infected with both HIV and HCV. Antiviral HBV therapy was applied in 21 (28%) patients and tenofovir monotherapy was the most prescribed medication. After approximately 2 years of antiviral treatment, the HBV-DNA viral load was undetectable in 12 (92.3%) patients and lower levels of alanine aminotransferase were found in these patients. CONCLUSIONS: Over a 13-year interval, very few individuals infected with HBV were identified, highlighting the barriers for caring for patients with HBV in developing countries. New measures need to be implemented to complement curative practices.

Molecular analysis of methicillin-resistant Staphylococcus aureus dissemination among healthcare professionals and/or HIV patients from a tertiary hospital

Abstract INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) is a nosocomial pathogen in community settings. MRSA colonized individuals may contribute to its dissemination; the risk of MRSA infection is increased in human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) patients, although the prevalence of colonization in this group is not well established. The present study addressed this issue by characterizing MRSA isolates from HIV/AIDS patients and their healthcare providers (HCPs) to determine whether transmission occurred between these two populations. METHODS: A total of 24 MRSA isolates from HIV-infected patients and five from HCPs were collected between August 2011 and May 2013. Susceptibility to currently available antimicrobials was determined. Epidemiological typing was carried out by pulsed-field gel electrophoresis, multilocus sequence typing, and Staphylococcus cassette chromosome (SCCmec) typing. The presence of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) and heterogeneous daptomycin-resistant Staphylococcus aureus (hDRSA) was confirmed by population analysis profile. Isolates characterized in this study were also compared to isolates from 2009 obtained from patients at the same hospital. RESULTS: A variety of lineages were found among patients, including ST5-SCCmecII and ST30-SCCmecIV. Two isolates were Panton-Valentine leukocidin-positive, and hVISA and hDRSA were detected. MRSA isolates from two HCPs were not related to those from HIV/AIDS patients, but clustered with archived MRSA from 2009 with no known relationship to the current study population. CONCLUSIONS: ST105-SCCmecII clones that colonized professionals in 2011 and 2012 were already circulating among patients in 2009, but there is no evidence that these clones spread to or between HIV/AIDS patients up to the 7th day of their hospitalization.

Secular trends in Klebsiella pneumoniae isolated in a tertiary-care hospital: increasing prevalence and accelerated decline in antimicrobial susceptibility

Abstract: INTRODUCTION Klebsiella pneumoniae has become an increasingly important etiologic agent of nosocomial infections in recent years. This is mainly due to the expression of virulence factors and development of resistance to several antimicrobial drugs. METHODS This retrospective study examines data obtained from the microbiology laboratory of a Brazilian tertiary-care hospital. To assess temporal trends in prevalence and antimicrobial susceptibility, K. pneumoniae isolates were analyzed from 2000 to 2013. The relative frequencies of K. pneumoniae isolation were calculated among all Gram-negative bacilli isolated in each period analyzed. Susceptibility tests were performed using automated systems. RESULTS: From 2000-2006, K. pneumonia isolates comprised 10.7% of isolated Gram-negative bacilli (455/4260). From 2007-2013, this percentage was 18.1% (965/5331). Strictly considering isolates from bloodstream infections, the relative annual prevalence of K. pneumoniae increased from 14-17% to 27-32% during the same periods. A progressive decrease in K. pneumoniae susceptibility to all antimicrobial agents assessed was detected. Partial resistance was also observed to antimicrobial drugs that have been used more recently, such as colistin and tigecycline. CONCLUSIONS Our study indicates that K. pneumoniae has become a major pathogen among hospitalized patients and confirms its recent trend of increasing antimicrobial resistance.

Prevalence rates of infection in intensive care units of a tertiary teaching hospital

OBJECTIVE: To determine the prevalence rates of infections among intensive care unit patients, the predominant infecting organisms, and their resistance patterns. To identify the related factors for intensive care unit-acquired infection and mortality rates. DESIGN: A 1-day point-prevalence study. SETTING:A total of 19 intensive care units at the Hospital das Clínicas - University of São Paulo, School of Medicine (HC-FMUSP), a teaching and tertiary hospital, were eligible to participate in the study. PATIENTS: All patients over 16 years old occupying an intensive care unit bed over a 24-hour period. The 19 intensive care unit s provided 126 patient case reports. MAIN OUTCOME MEASURES: Rates of infection, antimicrobial use, microbiological isolates resistance patterns, potential related factors for intensive care unit-acquired infection, and death rates. RESULTS: A total of 126 patients were studied. Eighty-seven patients (69%) received antimicrobials on the day of study, 72 (57%) for treatment, and 15 (12%) for prophylaxis. Community-acquired infection occurred in 15 patients (20.8%), non- intensive care unit nosocomial infection in 24 (33.3%), and intensive care unit-acquired infection in 22 patients (30.6%). Eleven patients (15.3%) had no defined type. The most frequently reported infections were respiratory (58.5%). The most frequently isolated bacteria were Enterobacteriaceae (33.8%), Pseudomonas aeruginosa (26.4%), and Staphylococcus aureus (16.9%; [100% resistant to methicillin]). Multivariate regression analysis revealed 3 risk factors for intensive care unit-acquired infection: age > 60 years (p = 0.007), use of a nasogastric tube (p = 0.017), and postoperative status (p = 0.017). At the end of 4 weeks, overall mortality was 28.8%. Patients with infection had a mortality rate of 34.7%. There was no difference between mortality rates for infected and noninfected patients (p=0.088). CONCLUSION: The rate of nosocomial infection is high in intensive care unit patients, especially for respiratory infections. The predominant bacteria were Enterobacteriaceae, Pseudomonas aeruginosa, and Staphylococcus aureus (resistant organisms). Factors such as nasogastric intubation, postoperative status, and age ³60 years were significantly associated with infection. This study documents the clinical impression that prevalence rates of intensive care unit-acquired infections are high and suggests that preventive measures are important for reducing the occurrence of infection in critically ill patients.

Microphysical evidence of the transition between predominant convective/stratiform rainfall associated with the intraseasonal oscillation in the Southwest Amazon

The distinction between convective and stratiform precipitation profiles around various precipitating systems existent in tropical regions is very important to the global atmospheric circulation, which is extremely sensitive to vertical latent heat distribution. In South America, the convective activity responds to the Intraseasonal Oscillation (IOS). This paper analyzes a disdrometer and a radar profiler data, installed in the Ji-Paraná airport, RO, Brazil, for the field experiment WETAMC/LBA & TRMM/LBA, during January and February of 1999. The microphysical analysis of wind regimes associated with IOS showed a large difference in type, size and microphysical processes of hydrometeor growth in each wind regime: easterly regimes had more turbulence and consequently convective precipitation formation, and westerly regimes had a more stratiform precipitation formation.

Frugivory by birds on Schefflera morototoni (Araliaceae) in a Cerrado-Amazon orest transition area, eastern Mato Grosso, Brazil

Schefflera morototoni fruits are important food source for neotropical frugivorous birds. The objectives of the present study were to record bird species that consumed fruits of S. morototoni in a forest in the transition Cerrado-Amazon Forest, Mato Grosso, Brazil and evaluate the potential of these bird species as seed dispersers of this plant species. During 31 observation hours, from November 1 to 5, 2011, 23 bird species were recorded consuming S. morototoni fruits. Out of these, 20 bird species were considered potential seed dispersers, as they swallow the fruits whole. The species consuming the greatest number of fruits were Aburria cujubi (24% of total consumed fruits), Pteroglossus castanotis (18%), Tangara palmarum (12%), Patagioenas speciosa (11%), Ramphastos toco (8%), and Dacnis lineata (5%). The species T. palmarum showed the highest visit frequency (VF = 1.51), followed by P. castanotis (VF = 0.80), and D. lineata (VF = 0.77). All bird species employed picking foraging method for removal of fruits and in 11 species (48%) this method was the only one used. Agonistic interactions represented 13% of the total number of visits. Dacnis lineata received the highest number of attacks and P. castanotis and Pitangus sulphuratus were the more aggressive species. The high bird richness and the great number of consumed fruits indicated that the fruits of S. morototoni may be an important food resource for birds in the Cerrado-Amazon Forest transition

Composition and ecological patterns of snake assemblages in an Amazon-Cerrado Transition Zone in Brazil

ABSTRACT The present study encompasses the species composition and ecological characteristics of the snake community in a Cerrado-Amazon transition zone in Midwest of Brazil (state of Mato Grosso). The data were collected during six excursions to the "Tanguro" (study area) by visual encounter survey, pitfall traps with drift fences and non-systematic sampling. We collected 194 specimens, distributed in 34 species, 26 genera, and eight families. The most abundant species were Crotalus durissus Linnaeus, 1758 (n = 50), Philodryas olfersii (Lichtenstein, 1823) (n = 15), Philodryas nattereri Steindachner, 1870 (n = 13), Xenodon rabdocephalus (Wied, 1824) (n = 12), Lachesis muta (Linnaeus, 1766) (n = 10) and Erythrolamprus almadensis (Wagler, 1824) (n = 10). The composition of species found here represents a combination of Cerrado and Amazonian savanna fauna.

Dynamics of experimental populations of native and introduced blowflies (Diptera: Calliphoridae): mathematical modelling and the transition from asymptotic equilibrium to bounded oscillations

The equilibrium dynamics of native and introduced blowflies is modelled using a density-dependent model of population growth that takes into account important features of the life-history in these flies. A theoretical analysis indicates that the product of maximum fecundity and survival is the primary determinant of the dynamics. Cochliomyia macellaria, a blowfly native to the Americas and the introduced Chrysomya megacephala and Chrysomya putoria, differ in their dynamics in that the first species shows a damping oscillatory behavior leading to a one-point equilibrium, whereas in the last two species population numbers show a two-point limit cycle. Simulations showed that variation in fecundity has a marked effect on the dynamics and indicates the possibility of transitions from one-point equilibrium to bounded oscillations and aperiodic behavior. Variation in survival has much less influence on the dynamics.

Changes in the Sexual Dimorphism of Triatominae in the Transition from Natural to Artificial Habitats

A shift from large to small average sizes was observed in Triatoma infestans and Rhodnius domesticus between field and domestic (or laboratory) conditions of life. It was more pronounced in the female specimens, leading to a subsequent reduction of sexual size dimorphism. This feature is discussed in terms of genetic and populational changes occurring from natural to artificial habitats, in particular those related to population densities. Sexual size dimorphism is then recommended as a new character to be used in the study of species of Triatominae adapting to domestic ecotopes.

Spatio-temporal dynamics and transition from asymptotic equilibrium to bounded oscillations in Chrysomya albiceps (Diptera, Calliphoridae)

The sensitivity of parameters that govern the stability of population size in Chrysomya albiceps and describe its spatial dynamics was evaluated in this study. The dynamics was modeled using a density-dependent model of population growth. Our simulations show that variation in fecundity and mainly in survival has marked effect on the dynamics and indicates the possibility of transitions from one-point equilibrium to bounded oscillations. C. albiceps exhibits a two-point limit cycle, but the introduction of diffusive dispersal induces an evident qualitative shift from two-point limit cycle to a one fixed-point dynamics. Population dynamics of C. albiceps is here compared to dynamics of Cochliomyia macellaria, C. megacephala and C. putoria.

Non-tuberculous mycobacteria I: one year clinical isolates identification in Tertiary Hospital Aids Reference Center, Rio de Janeiro, Brazil, in pre highly active antiretroviral therapy era

The aim of this study was to determine the prevalence of non-tuberculous mycobacteria (NTM) isolates at University Hospital, Reference Center for Aids in Rio de Janeiro, Brazil, during one year. We used standard biochemical tests for species identification and IS1245 PCR amplification was applied as a Mycobacterium avium specific identification marker. Four hundred and four specimens from 233 patients yielded acid-fast bacilli growth. M. tuberculosis was identified in 85% of the patients and NTM in 15%. NTM disseminated infection was a common event correlated with human immunodeficiency virus (HIV) infected patients and only in HIV negative patients the source of NTM was non sterile site. M. avium complex (MAC) was biochemically identified in 57.8% (49/83) of NTM isolates, most of them from sterile sites (75.5%), and in 94% (46/49) the IS 1245 marker specific for M. avium was present. Twenty NTM strains showed a MAC biochemical pattern with the exception of a urease-positive (99% of MAC are urease-negative), however IS1245 was detected in 96% of the strains leading to their identification as M. avium. In this group differences in NTM source was not significant. The second most frequently isolated NTM was identified as M. scrofulaceum (7.2%), followed by M. terrae (3.6%), M. gordonae (2.4%), M. chelonae (1.2%), M. fortuitum (1.2%) and one strain which could not be identified. All were IS1245 negative except for one strain identified as M. scrofulaceum. It is interesting to note that non-sterile sites were the major source of these isolates (92.8%). Our finding indicated that M. avium is still the major atypical species among in the MAC isolates recovered from Brazilian Aids patients without highty active antiretroviral therapy schema. Some discrepancies were seen between the identification methods and further investigations must be done to better characterize NTM isolates using other phenotypic and genotypic methods.